I'd say Mario Sunshine was a subpar 3D Mario game. I also found 3D World to be a bit disappointing, if only because it felt smaller and not very innovative compared to past titles like Galaxy.
Hum...Sunshine was pretty underwhelming, that's true. Kinda erased that one from my head although it's still a pretty damn good platformer overall, it really shines in certain parts but the whole goo thing, water mechanics and odd focus on plot dumb it down. Don't really agree with 3D World because that game is ridiculously packed with content, like all 3d Marios are. When it comes to small and disappointing, you just have to look at the "New" Mario series, it's a subseries composed of basically the same game since it always sold much more than the 3D Mario games for some strange reason. It seems they finally slowed down with those releases though.
SMW3D to me really felt like they had just realised they needed a Mario game on their system, so they used an idea from a 3DS game.
I assume that idea was making the title 3D "Land" to "World" because the games are, no pun intended, worlds apart.
